The Ending - An Explanation

WARNING: The following page contains major spoilers for the ending of BioShock Infinite.

So you're probably wondering what happened at the end of BioShock Infinite, particularly the Sea of Doors portion after successfully defending the airship and destroying the siphon. This section of the wiki will attempt to explain the meaning of BioShock Infinite's ending.

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When Elizabeth becomes omniscient, the knowledge of every universe is common to her and she realizes the implications are much bigger than Comstock and Columbia. She sees that the universes in which the "Booker" character lives lead to the inevitable: a man builds a city, attempts to leave society behind and create a utopia, which ultimately leads to corruption, downfall and destruction -- sometimes the destruction of Columbia, sometimes the destruction of civilization by Columbia. Players of the original BioShock will recognize one of many alternate cities as Rapture.

At the end of the game, Elizabeth takes Booker to the lighthouses so he can comprehend things and show him what needs to be done for the greater good. When Elizabeth asks Booker if he fears God, it is a hint that she is a moral person and may feel obligated to do the right thing.

After successfully destroying the siphon through use of the Songbird, Elizabeth now has full use of her ability, and is omnipotent. This is because the siphon was preventing her from using her abilities to their full potential. The only thing preventing Elizabeth and Booker from leaving Columbia behind and travelling to Paris at this point is Elizabeth's knowledge of the events leading up to this point. She now wants to stop the events that occurred at their source, Comstock's birth.

IGN Editors Discuss the Ending of BioShock Infinite

Elizabeth leads Booker through several lighthouses, including one which contains Rapture, a city which existed in the first two BioShock games. Through use of these lighthouses, BioShock Infinite simplifies the multiverse theory. The idea that surrounds this theory is that there are an infinite number of universes which exist, based on simple or extreme adjustments made which weren't made in others. To simplify, there is a universe in which Hitler died at a young age, thus several events following his leadership never occurred. This is where the "Infinite" in BioShock Infinite comes from. There are an infinite number of BioShock universes. In BioShock Infinite's case, Comstock came into existence, and created Columbia, whereas in BioShock 1 and 2, Andrew Ryan came into existence, and created Rapture.

Because of Booker's ability to use a bathysphere near the end of the game when Elizabeth brings him to Rapture, there's speculation floating around regarding Andrew Ryan's true identity. Most signs point to Andrew Ryan and Comstock being one and the same, but we will know the truth in due time.

In BioShock Infinite, we're given two main universes. One in which DeWitt accepts his baptism and eventually becomes Comstock, thus leading to the creation of Columbia. The second is where DeWitt refuses the baptism, thus creating the man you play as throughout the game.

The crucial point in Booker DeWitt's existence is that of the baptism which occurs after the battle of Wounded Knee. Because of this decision at the baptism, there are two main universes which exist in BioShock Infinite. Booker either accepts or denies the baptism.

In the first universe, Booker declines the baptism and remains himself, has a daughter named Anna, owes a great debt through his gambling addiction, and gives up Anna to Robert Lutece, who is working for Comstock, in order to pay the debt. He changes his mind at the last second, and while trying to pull Anna away from Comstock, who is escaping through a tear created by Rosalind Lutece's machine, her pinky finger is cut off as the tear between their universes closes.

The Booker in this universe lives in regret and depression for about 20 years. At some point during this time, he brands "AD" on his hand, standing for Anna DeWitt. Booker is eventually pulled over into Comstock's world by Robert and Rosalind Lutece. Booker invents an entirely different story within his mind in which he is tasked to retrieve a girl in order to pay off his debt to a man in New York. This is where the opening quote in Infinite by Lutece comes into play: "The mind of the subject will desperately struggle to create memories where none exist." DeWitt needed a reason to be in this alternate place that wasn't entirely his own; his imagined story helped his mind remain stable. This also explains the conversation between Booker and Elizabeth when he says he had never heard of Columbia before arriving there. The city simply did not exist in his universe.

From here, there are several different possible scenarios, one of which is the scenario you experience within BioShock Infinite. The others are presumed to have lead to Booker's death. Any other universes within the game that you experience such as the one in which Booker joins the Vox populi were created by Elizabeth. This means that they didn't exist before she needed them to.

In the second universe, Booker accepts the baptism and becomes Comstock, creates Columbia, and foresees the future through use of Rosalind Lutece's tears in the universe. He looked into the universe in which Booker, the false shepherd, attempted to overthrow him. In this universe he also saw his own daughter lead Columbia after his death, and drown in fire the mountains of man. Before confronting him, near the replica of the siphon, there are panels depicting your exploits in Columbia, the last of which is Comstock standing at the basin. Because his exposure to these tears made him sterile, he had to open up a tear into a universe in which he had a child and retrieve her.

In the Sea of Doors, we see other instances of Booker and Elizabeth. This means that ours is not the only Booker to make it here. Since there are only a few Elizabeths at the baptism, it could be that there are clusters of universes; most of them do not have an Elizabeth that gets her full powers back, but one universe does. Thus, the other Bookers we see walking are each closing their own cluster of universes. It could also be implying that the other pairs we see are other players who finished Infinite.

At the end of the game, Booker/Comstock once again approaches the baptism scene by the river and is joined by different versions of Elizabeth/Anna who have stepped into this universe and timeline. With their help, Booker finally realizes he is also Comstock. The previous two choices lead to the repeating cycles -- the Elizabeths know that the only way to break out of them is to disrupt the "always a man, always a city" world order and destroy "the man" before he builds the city. The Elizabeths drown Booker; and he doesn't struggle much as he resigns himself to his fate.

The circle is broken and Booker no longer becomes Comstock. As the Comstock universes collapse and Anna is no longer pulled into them, the different grown-up versions of Anna/Elizabeth -- who were pulled into this final, altered universe -- disappear one after the other.

In the universe where Booker DeWitt exists, Robert Lutece is born rather than Rosalind Lutece. In the universe where Booker becomes the version of Comstock we see in the game, Rosalind Lutece is born rather than Robert Lutece.

Prior to meeting Comstock, Rosalind Lutece's research in the existence of a floating atom lead her as far as the creation of that atom, and a means of which she could communicate with Robert Lutece through Morse code. It wasn't until she received funds from Comstock that she was able to create a machine that could open tears into other universes. This benefited her ultimate goal at the time, which seemed to be acquiring Robert Lutece.

In the Booker's universe, Robert Lutece is assigned with the task of retrieving Anna DeWitt from Booker. At the point which this exchange takes place, a portal is created between the two main universes in order to bring Anna to Comstock. Rosalind is on the receiving end, and attempts to get Robert to come through the portal as well so they can be together. Booker makes a last minute decision that he wants his daughter back, and attempts to pull her away from the tear, but is unsuccessful and her pinky finger is cut off.

Many years later, Robert Lutece, being remorseful for stealing Elizabeth from Booker and setting her on a path to attack those living on the surface of earth, gave Rosalind an ultimatum that he would leave her life if she did not help him send Elizabeth back to her own universe. Comstock, whether aware of this plan or just trying to destroy any chances of word of what he had done getting out, ordered Jeremiah Fink to sabotage the machine to kill Robert and Rosalind. However, their consciousness was instead fused with the possibility universe, giving them apparent immortality and ability to travel through time and space. This would make it easier to carry out their plan.

It should also be noted that early in the game, when the Luteces had Booker flip a coin, Robert carried a chalkboard with heads marked many times. When Booker is asked to choose, he either says heads or tails, but the coin will always land on heads, as it is a constant. It is revealed later that Robert conducted experiments on different Bookers in different timelines to try to change his choices. The telegram about not picking the #77 baseball, the coin flip, the choice of pendant, etc. were all attempts to do this, but as Elizabeth explains: "There are constants and variables."

From the beginning of the game, the Luteces know what's going to happen, because they've been through all of it before with other Bookers. Think of your playthrough of the game as Booker's hundredth or so attempt at preventing Comstock from ever existing.

It could be said that it's Booker's 122 or 123rd attempt, based on the bell-ringing combination at the lighthouse: 1x 2x 2x. Also, after you flip "heads" early on in Columbia and the Luteces mark a 13th notch on the chalkboard, Robert turns around and there are 2 columns of 11 sets of 5 notches, making 123 total notches including your playthrough.

During the beginning of the game while in the boat with the Luteces, Rosalind asks Robert if Booker rows. Throughout each and every attempt they've made to get Booker to Elizabeth, he's never helped row the boat. This was a minor detail Rosalind forgot.

There's a man who Booker finds dead at the lighthouse. This was likely a man sent by Comstock in order to prevent Booker from making it to Columbia. It's also likely that during one of the first attempts to get Booker to Elizabeth, this man killed him. Thus he was killed by the Luteces during any attempts after this one. A note found in the lighthouse that reads, "Be prepared. He's on his way. You must stop him. - C" The C stands for Comstock. This was probably a letter left for whoever the dead man is.

When Rosalind hands Booker the shield during the Comstock Center Rooftops portion of the game, both her and Robert are surprised that it doesn't kill him. This was likely an experimental item that killed Booker in other previous attempts.

There are other various moments in the game which indicate that Booker's been through all of this before, and the Luteces almost treat him like a lab rat in a maze.

In the event that the player gets Booker killed during the game, you often see the black and white flashback to Booker's office again. It is possible that the game treats your "respawn" with that Booker actually having died, while you then continue playing as yet another Booker, one who makes a better choice at that time to prevent his death.

She received her powers from the point in time which she lost her pinky finger. The portal closing on her affected her and gave her the powers because it resulted in her partially existing in two universes at once.

This is supported by the early voxophone titled "Source of Her Power" where Rosalind states: "I suspect it has less to do with what she is, and rather more with what she is not. A small part of her remains from where she came. It would seem the universe does not like its peas mixed with its porridge."

If you managed to stick around after the game's credits rolled by, you would have found yourself back in Booker DeWitt's PI room. Turning toward the right and entering Anna's nursery, he calls out for her, and the game ends before you find out if she was in her crib.

One theory is that through Comstock's death at the baptism, the only universe which remained was that in which Booker declined the baptism, and never attempted to sell his daughter. In this final universe, Booker and Anna are assumed to live happily ever after.

In response to a fan on Twitter who asked "Why do not you just answer me if Anna´s in the cradle or not? LOL", Ken Levine (writer and creative director of the game) replied with "--Did you read about the cat?" The "cat" in question is probably Schrodinger’s cat. One conclusion of the Copenhagen Interpretation of 1924 stated that a particle could exist in a infinite amount of states before being observed—a quantum superposition. In order to ridicule this, Erwin Schrodinger asked his colleagues to imagine a cat in a box with a vial of poison set to break at any time. Before opening the box, one cannot know if the cat is alive or dead. Does this really mean that the cat is both alive and dead at the same time? Neils Bohr et al. argued yes, and there's has been the prevailing interpretation of quantum mechanics since. Having just read about the cat, we can assume that as the game cuts out before we are able to observe the crib, Anna is both in and gone from the crib.

Elizabeth's fate is still rather up in the air. It is possible she exists within the probability space like the Luteces.

1. The first sea of lighthouses you encounter, with all the "stars" (which are really tears) represents the Bioshock multiverse.

2. From there you enter the Columbia megaverse, a subset of possibilities within the entire multiverse all having to do with Columbia/Elizabeth/Booker.

3. You enter a final light house where you're drowned by parallel universe Elizabeths.

4. But Prime Elizabeth never enters that lighthouse with you. The Elizabeth in this lighthouse/universe isn't wearing the bird/cage pendant. Booker even says "wait, you're not, who are you?"

5. So Elizabeth is still outside, hanging out in the Columbia megaverse. If drowning Booker eliminates the Comstock timelines, this could be visualized as all the lighthouses (universes) containing Comstock popping out of existence in that sea of lighthouses.

Elizabeth doesn't necessarily disappear, because she's shown to be detached from the Bioshock time/space continuum by having the ability to open/enter tears and megaverses at will.

6. The question is, what's she doing now? Sitting around in that endless sea of lighthouses? Knowing the constants and variables of each one? Can she visit Booker, and would she even want to? The ending tangentially opens new questions, infinitely, so to speak.

By the end of the game, the Elizabeth with whom we traveled was omniscient and quasi-omnipotent. It seems reasonable to conclude that she was able to remove herself from the Comstock timeline, to survive the erasure of the Columbia universe.

Second Theory: Elizabeth and Transfering One's Consciousness

One can also make the case for Elizabeth transferring her consciousness. Booker wakes up in the post-credits scene and clearly, on some level, remembers the events of Infinite. If Booker remembers the events of the game, then it is possible that he will not go on to repeat his mistakes (i.e. lapse into alcoholism, gambling, etc.) Also, if he remembers, he can instill within his child the same sense of intellectual curiosity, love of life, etc. that the girl we came to know possessed. And finally, if he remembers, it is possible that baby Anna will also come to acquire memories of the events that transpired within the game (and, for all intents and purposes, become the Elizabeth that we knew in the game).

Third Theory: The Disappearance of All but the "Final" Elizabeth

Even if one wishes to argue that "prime" Elizabeth (the person with whom Booker travels during the events of the game) enters the final lighthouse, her fate is still unclear. We do not actually witness the disappearance of the "final" Elizabeth. Some have contended that the final piano chime symbolizes her disappearance as well, but that is conjecture. One could make the counter-argument that if Ken Levine wanted us to know that the "final" Elizabeth disappears, he would have shown it. To quote Andy Kelly at CVG, "The sudden cut to the credits is obviously intended to make this ambiguous, leaving players to decide her fate for themselves."

Booker's death at the baptism would have brought an end to Elizabeth's existence. Resulting in Booker not having the opportunity to be drowned. Comstock and any Booker that interacted with Comstock would have to die.

Booker's death at the baptism prevented the birth of Comstock, and therefore the creation of Columbia. The interactive cutscene that plays after the credits have rolled is an entirely different story that suggests there is a universe in which Booker and Anna don't confront Comstock or a debt, as explained in the previous section.

However, this is unlikely because Booker's death at the Baptism would prevent every possible scenario of Anna's birth from ever coming into being. Anna's birth requires Booker's denial of the Baptism (although Booker's denial of the baptism may not necessarily lead to Anna's birth). Even if Anna was born before the Baptism, Booker's dying still prevents him with living with her in any universe. Thus, the potential for a Booker/Anna happy life universe is both impossible and implausible.

If you view Elizabeth for what she is however, and how her ability is beyond that of any machine created by the Luteces, you can see where her acts near the end of the game can avoid following most logic. Her goal when drowning Booker was to end Comstock's existence, not Booker's. By drowning Booker, she prevented the creation of Comstock in any universes, and thus eliminated any universes with Comstock in them. This allows for the cutscene at the end in which Booker still has Anna in his possession. Now if only he could get some therapy for his gambling addiction.

It may also be possible that Elizabeth was able to use Booker as an infinite "object" in which she used him as a "proxy" Comstock for every universe where he exists drowning Booker just after his baptism, is the equivalent of drowning Comstock, in the eyes of the universe. This is why multiple Elizabeths appear, and why there are no longer any people at the baptism with Booker. The Elizabeths have merged this moment together with all universes, and at the same time have separated it from time. This way they conduct it as a "play", Booker plays Comstock and is killed in his place. In other words Booker is drowned which is then used as the universal ending, for any universe where Booker accepts the baptism as he cannot be drowned by refusing the baptism. Rendering the image shown at the end as a universe where Booker refused the baptism (now the only feasible one, as any Booker who accepts is drowned to death). Anna is a child when Booker awakens as this is the day (as shown by the calender on Booker's desk) that Anna was sold, thus he returns to this day where his universe is starting anew. An idea left in the air is whether Booker remembers his ordeal, and if Anna exists here or not. Booker awakens startled in his chair (hinting at waking up from a nightmare) and immediately calls out Anna's name (implying that he's afraid it hasn't worked) before cutting to black we see a crib in the corner of the room (implying we exist in a universe with Anna). Otherwise Booker's just a creep with a nursery and no child.

A majority of the content within this theory is incorrect, and the explanation which eliminates the need for this theory has already been given above. Elizabeth never states that she must kill Booker before he becomes Comstock. In fact, Comstock is killed in the end of the game, as Booker becomes Comstock while beneath the water. The only change here is that any Booker who accepts the baptism is drowned and never resurfaces.

Many theories are not able to reconcile how it was possible that a non-Comstock, post-baptism Booker was alive in the scene following the credits, or forget that Elizabeth specifically says that she needed to kill Booker *before* he made the choice whether to be baptised. Being that he was drowned before the decision, neither version of Booker/Comstock would live. However, this can be explained with a paradox and the theory that nature will always correct a paradox.

If Booker always refused the baptism, he would continue to live and have Anna and would never have to give her up to Comstock. But being that this choice is a variable, Booker choosing to refuse it means there are always universes in which he accepts the baptism and becomes Comstock, resulting in some version of the events of the game. This includes Elizabeth becoming omnipotent and drowning Booker before the baptism.

However, the act of drowning Booker before the baptism means that Elizabeth would no longer have ever existed, and would therefore not have been able to drown him after all. When Booker accepts the baptism, it leads to the series of events that results in Elizabeth becoming all-powerful and drowning him before he even makes the decision. Because of this fact, the choice to accept the baptism creates a paradox, meaning it is not a possibility. This means that the only possibility allowed by nature is to refuse the baptism, making the refusal no longer a variable, but a constant. Thanks to Elizabeth, no branching universes are created at this point and Booker goes on to raise Anna without her being taken away by an alternate version of himself.

The problem with the Paradox Theory listed here is that if there are infinite universes, i.e. infinite post-baptism-refusal Bookers for the Luteces to choose from (which the game seems to imply that there are), there is not only one Booker who goes to the river to consider the baptism but infinite. In other words, alternate universes are branching off constantly and at all variable points, instead of the single arbitrary point of whether or not Booker chooses to be baptized. Only this constant branching could provide infinite post-baptism-refusal Bookers to the Luteces, since universes would need to be branching off constantly based even on Booker's minor decisions. But if Booker's minor decisions after the baptism decision result in the creation of new universes, so do his minor decisions before the baptism.

This means that there are an infinite number of Bookers in different universes all go to the river and have a chance to make the baptism decision.

Drowning Booker before he is baptized (in one of these, as happens in the ending) then eliminates the infinite number of worlds in which that Booker becomes Comstock and in which fire rains from the sky, etc., but there still remain another infinite number of worlds where slightly different Bookers accept the baptism, and an infinite number of Comstock worlds branch out from each of these.

This is incompatible with the idea that all the universes collapse except for one in which Booker keeps Anna, but supports the idea that the other Bookers and Elizabeths seen on the docks in the end come from other parallel worlds in which Booker succeeded in rescuing Elizabeth and defeating Comstock, and that those Elizabeth/Booker combinations are all on their way to other versions of the baptism scene to shut down other infinite-branches in which Booker becomes Comstock.

In two Voxophone recordings (#003: Everyman, All at Once and #079: The Mirror of Sin), ZH Comstock asks what happens to the man "left behind" or "lies submerged" in the baptismal water. Similarly, Elizabeth asks Booker how he deals with all the things he's done shortly after he rescues her and he replies that he just learned to live with them. One of the central themes, then, is whether or not a man can truly leave his sins behind him by participating in a ceremony. Despite being baptised, washed of his sins and born again, Comstock goes on to commit further atrocities despite Wounded Knee ("burnt the teepees with the squaws inside"), possibly because he believes himself to be truly another person following the baptism. However, he remains the same ruthless, cruel man internally.

Watch the ending of BioShock Infinite

In this sense, then, the drowning death of Booker at the end of the game could be viewed, not as a physical death, but as a metaphysical one where Booker relinquishes the concept that his sins can be washed away solely by the act of baptism without an internal change. By accepting this, all of the alternate realities where Comstock existed are closed off and Booker is reunited with an infant Anna/Elizabeth.

Does this Booker have any knowledge of the events in the game, like a bad dream? I think so. Elizabeth asks Booker near the end if he is afraid of God and he answers in the negative. I'd like to think that Booker has been shown Divine Grace.

This idea is purely theoretical and has little or no basis in the facts as presented by the game. It does however reconcile many of the paradoxical issues that other theories are plagued with.

The idea is centered on two facts within the game:

1) During the course of the game Elizabeth states that when she was young, she not only had the ability to create tears but she had the ability to create whatever was in her mind.

2) Upon entering the baptism sequence for the final time, Booker says something to the effect of "why are we here again?" To which Elizabeth responds, "it's not the same."

The thought is that the final baptism sequence is a place wholly of Elizabeth's creation and not an actual place within any of the timelines - a place outside of all universes. This is reinforced by the fact that the people that would have been present for the baptism do not appear in the final sequence. In essence, the final scene is symbolic in nature and not literal. Elizabeth has created a place where drowning one Booker can stand in for killing however many Bookers as is necessary in order to stop the creation of Comstock in all universes. You could also say that one sacrificial lamb cleanses away the sins (Comstocks) of all Bookers in all universes.

Thus it could then be theorized that only the Bookers who accept the baptism die (who's to say how this symbolic drowning would manifest? They may die soon after or even before the baptism) leaving all the Bookers who refuse the baptism to live on - giving us the final scene after the end credits.

Bioshock as a series has always been about ideology. Digging below the surface of the first two games reveals distinct references to and discussions about the philosophies of Ayn Rand. Bioshock Infinite takes this idea an entire step further by tackling numerous ideas and philosophies. Namely, Bioshock Infinite includes themes about American Exceptionalism, Absolutism, Objectivism, and the concept of redemption among others.

Booker's first few moments in Columbia are potentially meant to present some overly optimistic caricature of the American dream and one view of the American past. Very, very quickly the game takes a darker turn and soon we see a different side of Columbia. This time Columbia is a much more pessimistic view of the American dream and the American past, which includes a moment where characters dressed in a way that heavily resembles the Ku Klux Klan shooting "Crows" at Booker. However, both of these views are essentially caricature, and neither of them are entirely true or false, from a certain point of view. They are both two sides of the same coin.

BioShock Infinite, then, reveals itself to be about perception and self image, and uses other thematic elements as a framing reference to approach this central theme. Initially, the game looks at war and heroism. Booker's assault on Comstock examines how we might might dress up or distort our own pasts to cope with our misdeeds or failures. The motorized patriots are a symbol for the false effigies of past idols we create and use to justify our actions and beliefs.

Infinite goes on to frame it's discussion on perception using themes of class warfare, first exaggerating the atrocities perpetuated on the working class, and then revealing their hypocracies.

At no point does the game exempt Booker, and therefore the player, from anything he or she sees. Because Booker worked for the Pinkertons, he is, in a way, guilty of creating the state of places like Finkton. Because, in one reality, Booker is a hero to the Vox Populi, he is guilty of their crimes as well. Because Booker, in one reality, is also Comstock, he also bears his crimes.

BioShock places the burden of responsibility for the entire state of the world on its players and then, in its ending, it explains why this is. Elizabeth and the Luteces explain that reality isn't objective at all, as Rand so strongly asserted. According to BioShock Infinite, there are countless perspectives and views of the same thing and each one is just as real to it's own believer or creator.

Booker was a divided man. He wrestled with the guilt of his past and pondered whether he could ever be cleansed of his sins. The Booker that became Comstock believed that, indeed, we can all be forgiven for what we have done, and forget what came before us. The Booker that fought Comstock rejected that notion, believing that we have to live with our sins for the rest our lives. Then in the final moments of the game, Booker ends his life drowning in waters in Baptism, finding the space between redemption and damnation. Maybe, the game is asking us to look at both sides of every coin.

The question that bugged me the most at the end of the game was: "Why does Booker have to be drowned when we (player/Elizabeth) want to kill Comstock?" since the two were clearly distinct persons 20 years after the baptism. Killing the Booker who lives in an alternate universe 20 years after the baptism won't do a thing to the Comstock would-be at the baptism. But since all (almost all?) the Elizabeths are disappearing at the end we can assume something happened. Some effect did take place. Therefore one possible explanation is that: "The 20 years ago Booker who would become Comstock was indeed killed, and the playable game character Booker was only experiencing/remembering that event." This idea of remembering one's death is supported by lots of enemies during the Chen Lin chapter. This idea also gives reason to Booker waking up at the end of credit.

Another question that bugged me was: "What happened when Booker crossed the tear for the first time when the Luteces came to pick him up in their raincoats?" From both Robert Lutece and Comstock we know the first cross is not an easy event (Lutece was greatly concerned and Comstock was made sterile). Elizabeth also crossed a tear but she got her pinky cut off the very first time so she is a special case compared to Lutece & Comstock, or anyone for that matter. Back to topic, when Booker first crossed a tear for the "first time", he fainted and fell down on the floor (I personally cannot determine whether he did cross the tear). I used the quotation mark because from last paragraph I am now suggesting everything that happened to Booker when he entered any door in "sea of doors" is merely a piece of experience & memory, his physical body does not have to go through the process. Hence the player controlling him to cross the tear for the "first time" was only a piece of experience & memory. But that is again off-topic. To make some sense of this we have to answer one more question.

"What is with the death/respawn scene when Elizabeth is not there to revive Booker?" In short, when Elizabeth was not around, Booker's death will bring him to a door which looks greatly like the front door of his PI office. He opens the door and back into the game he goes. Similar mechanism (with more emotional contents) was displayed a few times in the game as plot, like at beginning of the game when Booker was "drowned" by the preacher before he enters Columbia. I came up with one idea to help myself understand this:

Every time Booker crosses to a different universe, his consciousness enters the body of the Booker in that world. If there is a conflict, he creates a new body. The real physical body of his is back in his PI office because it was not able to cross the tear (Robert Letece's body was ok with the crossing, apparently). If the Booker in another universe is killed, his consciousness slips back to his original body, ready to cross again. Being able to do this is what Booker got for crossing the tear. The same rule can also hold true for Comstock, no contradiction was found so far. In the Chen Lin chapter there is one universe where Booker is a martyr and no living body was in existence thus I added in the creating body idea. Later I realized I also have to reconcile the fact that his consciousness did not enter Comstock's body (duh) so I used the word "conflict." Here the conflict might be physical or cognitive. Booker does not identify with Comstock in both thought and body. I have not yet determined which is the reason his consciousness did not enter Comstock as it entered the Comstock would-be from 20 years ago.

Alright here's the deal. The protagonist that you play, Booker/Comstock, is analogous to Schrodinger's cat, which is both alive and dead at the same time. This is quantum mechanics, and it's what makes possible multiple realities simultaneously. Each reality has it's own set of events based on events and decisions made. This part in itself is fine, as events are self-consistent within the chain. Thus, Booker never solely accepts or rejects the baptism, it's always both. I know of no means by which it is possible to have only one outcome due to quantum entanglement (see below), which is why the ending is impossible.

The next issue that arises from this is Quantum Entanglement (Einstein called it 'spooky' action at a distance, it is quite spooky.). Entanglement occurs when two objects are non-locally connected and transfer information instantaneously. Thus, if you have a quantum coin that is both heads and tails, connected to a like-wise coin across any given distance. If you measure/observe one quantum coin that is heads, instantaneously, the attached/entangled quantum coin will be tails. Einstein was right to call it spooky, because it appears to violate relativity if information is traveling at higher than relativistic speeds. However, what is actually happening is that two realities are co-occuring simultaneously, just like Schrodinger's cat being both alive and dead at the same time. Thus, when the Elizabeths make the choice to drown Booker, they are quantumly entangled with other Elizabeths, and their choice (just like the coin), will result in a binary opposite choice, again via quantum entanglement. Thus, by choosing one outcome (Booker dies), they are determining simultaneously that an alternate outcome of Booker lives occurs. This makes it impossible for them to ever be rid of Booker, by their own choice no less. It seems paradoxical, but it's actually kind of funny.

What's more complicated, and this I cannot give any answers to, is that the laws of quantum mechanics are held up so long as they're self-consistent within their own reality (set of events). However, we see multi-chain events interacting, with the issue of quantum entanglement. This makes it no longer self-consistent, albeit theoretically it can probably be dealt with, but no further at this point. Quantum Entanglement is hard enough in one universe, let alone applying to multiple co-occuring realities.

For anyone concerned with resolving infinite sets of universes, this issue of infinity can be resolved by number, and more specifically set theory in mathematics.

I don't expect the Bioshock team to know about things like Quantum Entanglement, set theory, etc. This is a fictional video game. Further, there is "suspension of disbelief," where you put the real world aside in order to enjoy the fictional one you're presented with. This really only works with a good story, and Bioshock Infinite delivered (for me anyway).

TL:DR - Booker DeWitt simultaneously being Comstock can be analogous to Schrodinger's cat. Quantum entanglement literally makes the ending impossible. Infinite universes can be resolved by using number, and primarily set theory. "Suspended Disbelief" is how I enjoyed the ending.

The game simplifies the many worlds theories from physics a bit, but it also does this a little inconsistently, some aspects use a simplified model, others don't. (As a side note, many worlds theory was popularized by a guy called Bryce DeWitt...)

The game argues that after the baptism, Booker will either remain Booker or become Comstock. So by ending his life before the choice is made (and Elizabeth does say this, it must be done "[...] before the choice is made") no timelines with Comstock will come to pass. Killing Booker at this time will also remove all non-baptized Bookers from the following timelines meaning Elizabeth will never be born. The key aspect here is the subsequent timelines are affected.

But then what about the final scene? And what about the last Elizabeth that doesn't disappear before fading to black?

Well here is where the simplification sort of comes in, there aren't many (possibly any) constants in the world. Also, the many worlds theory prevents paradoxes since every event creates a new universe and no universes are destoryed. If i go back in time and kill my grandfather, that event created a new universe. I'm not killing my grandfather, i'm creating a new universe that would had a duplicate version of me, had i not killed that duplicates grandfather. This is one reason why this theory is useful in quantum mechanics.

Infinities are a little funny. You can split an infinity in an infinite number of bits (or sets) and each set could have any number of elements, including an infinite amount. This also means that in an infinite set of outcomes, even the tiniest possibility will be guaranteed to actually occur, no matter how unlikely it is.

So in the game, some universes had the original baptism and some didn't, but how many exacly? Infact there are a basically infinite number of universes with both alternatives (since an infinite set can have an infinite number of subsets, each with infinite elements) this means that there would likely be a very large number of omnipotent Elizabeths that would all show up at the final scene. That would probably overload my gpu though, so there is only a couple :)

Now given that there are an infinite number of universes, and that all events, not only the baptism, spawn "new" universes, its entirely plausible that there is one (or infact infinite) universe(s) where Booker doesn't gamble, or doesn't make a deal to sell Anna, or by some other means enables the final scene. (This is the slightly inconsistent bit.)

The game portrays the baptism as a constant, but there really isn't basis for that, there might be any number of universes where Booker never went there or didn't even do the bad things that caused him to consider the baptism in the first place.

The game does establish that Booker can have dreams from "other" universes with the burning New York, so the Booker in the "final scene" universe could have dreamt of the events in the "player" universe. (Though both of these would be equally "real".)

The final non disappearing Elizabeth (at least if we argue she doesn't disappear) could come from such a universe, she is arguably not the same Elizabeth we've seen all game as she is missing the pendant. The disapearing Elizabeths are also a little inconsistent with the many worlds theory, since they would not be destroying the future universes as much as they would create new ones where the events of the game never happened. The Elizabeths however would still originate from universes where the events did happen, so they would remain. That would be a very bleak ending though since they would never be able to prevent the games events no matter what they did. (They'd only create new universes without those events.)

Is this what Mr Levine had in mind when he wrote this? I dunno, but it is a viable logical solution to what we see at least :)

Now, whats really interesting is the last couple of voxophones, such as "the ultimatum" where Rosalind talks about Robert and how he wants to reverse what they have done. Rosalind notes that she result is going to be sad but that she will go along with it.

From this it would seem that Robert and Rosalind pull Booker in to the (or should I say one of the) Comstock realities and actually set the events of the game in motion because Robert feels remorse about the baby buying thing.

But then why didnt they just go back and not buy the baby in the first place instead of going from universe to universe looking for the one where Booker is able to defeat Comstock? Who knows :)

Because of the "constants and variables" idea almost any ending you conceive has happened, is happening, will happen. If you look at it this way, we are all right.

A note on the post credits scene.

The scene is actually quite easy to explain, although Booker dies at the baptism, this only prevents all versions of Comstock being born, not all versions of Booker, it should be noted though that the Booker that you play as does indeed die, but the alternate versions of Booker are still alive, and since Comstock never existed, Anna is never taken, meaning it's very likely that she is in the crib. To conclude, in the post credits scene, you play as an alternate universe version of Booker in which Comstock never existed, therefore Anna is not taken, and this Booker and Anna live together, whether or not Booker still gambles among other things is unknown though. (As there can be many incremental differences between universes.)

A fair number of the arguments presented here have already been mentioned in one form or another. I am however surprised that this has not appeared so far, so this theory is supposed to be a concise unified final solution.

The term "infinite alternate realities" is thrown around quite often (not just in reference to Bioshock), but it seems to me that the background and true implications of the Many Worlds Interpretation [MWI] generally fail to be acknowledged. To put matters into perspective, think about the following:

In reality, the 'entire' universe may be much bigger or in fact infinite in size, however our observable universe is very much finite (91 billion light years across). This is crucial, because everything outside of the cosmological horizon is fundamentally inaccessible to us, i.e. no information from beyond the horizon can ever be acquired. Naturally, any finite system only has a finite number of non-redundant configurations. Moreover, since the vast majority of the universe is practically irrelevant to events that take place on earth (after all, the number of grains of sand on a planet in another galaxy does not affect earth's history in the slightest), we really only need to look at alternate universes in which something on earth is different. The number of those is actually very easy to calculate. There are roughly 10^50 fundamental particles (a few per atom) in the earth, so the single perturbation count (the number of possible alternate earths with the same number of particles) is (10^50)! = 10^10^64. That is a fairly large number, but decidedly finite.

Crucially though, this not only includes instances where you are wearing a differently coloured shirt or did have something else for breakfast, but extends to universes in which the events of Bioshock (or any other fictional story) actually transpired on earth, and even includes absurdities like the earth not being a rocky spheroid but rather an equilateral cube made of pure gold. Obviously, most of these earths are uninhabited or uninhabitable altogether and even the ones that are vastly different in terms of human civilization and history are generally disregarded when people are referring to alternate realities.

Taking into account all the MWI's implications has significant impact on the game's interpretability. For one, it would mean that all the choices Booker and Elizabeth make are basically meaningless since there always is an alternate reality in which their alter egos made the exact opposite choice. Though Elizabeth in particular would still be in a desperate situation (after realizing that she cannot change anything), this would make the characters far less relatable in my opinion, because their problems are more detached from reality, and the game is not about nihilism anyway.

[On a philosophical side-note, I'd like to add that in the real world, we do not usually succumb to complete apathy in the face of the MWI because there is no interaction between parallel realities and ours and so they do not concern us. For Elizabeth however, who can travel between worlds, the realization that there is absolutely no change she can effect would presumably be devastating.]

Secondly, the ending would not make sense because preventing the baptism would be ultimately futile, as in reality universes cannot be destroyed since their existence is tautological, and even if we grant that caveat, there would still remain other universes in which Booker does not cease to exist. In some he would not have become a drunk in the first place, or would not have sold his daughter, or genuinely changed his character irrespective of the baptism. In the real MWI there are no necessary constants across alternate universes; there is no reason to assume that the baptism is a fixed anchor across all realities or that all alternatives branch from such a one.

Therefore, I would suggest that for the sake of the game's coherence and integrity it is a much healthier approach to assume that not all possible alternate realities exist, but only those that are in fact created by Elizabeth or the Luteces, all branching off of the prime one (which would have to be one in which Booker becomes Comstock). The first alternate reality is created by Rosalind during her first successful experiment, at most a few years before the baptism. Robert and Rosalind continue to create branch-universes while they are working for Comstock and Elizabeth starts doing the same as soon as she begins to display her ability. The fact that in this scenario the first parallel universe is created only after the events of Bioshock 1 and 2 transpire in Rapture is not a contradiction. For one, every universe is of course created with a complete and self-consistent history (it's not like its inhabitants don't remember anything before a certain date) and in addition, time is not universal across the multiverse but unique to each one. That is to say there is no simultaneity between them. [Otherwise the MWI would not be able to explain time-travel, among most other things about quantum physics.]

This means there are fairly few universes within the game, possibly as few as 123. During the ending sequence Elizabeth first speaks of thousands and later 'a million millions', but I'd interpret that as her (being overwhelmed herself) essentially saying 'very many', maybe billions, but definitely not infinitely many. When she says “all the choices lead us to the same place – where it all started” it again suggests that not all, but only those universes exist that branch off of the prime one. As a result however, choices become meaningful. When Elizabeth first passes over into a new world during the game (after finding the dead Chen Lin, disregarding minor forays before), Booker tells her that she does not create new realities but only opens doors to pre-existing ones. He would be incorrect, but that's all right since he doesn't know better and only tries to comfort her. This approach is backed up by the out-of-phase soldiers in the prison. The newly created reality differs from the prime universe mainly insofar as certain people are dead in one and alive in the other. Had all possible realities been actualized before, every single human would be phased out since there would always be a world in which they are not alive. Therefore Elizabeth is implicitly responsible for creating a whole new world in which people suffer, which makes her a beautifully tragic and relatable character.

In the end then, after the Siphon is destroyed, she essentially becomes God (of the entire Bioshock multiverse). This is practically canon and supported by many in-game hints. She explicitly says that she can see all universes (omniscience) and when she opens a tear immediately after the Siphon is destroyed, it is implied that she not simply opens a tear where there already was a crack like before when she did not know she was creating new universes, but rather is now aware what she is capable of and wilfully actualizes the gateway to Rapture and the sea of doors (omnipotence). The presence of other Booker/Elizabeth pairs there would normally be a contradiction, since the drowning would only happen once, making additional occurrences of the event redundant. It's reasonable then, to assume that the sea of doors is not a 'real' (in the sense of natural) place – a universe existing solely as a hub to other realities seems rather artificial – but rather one created by Elizabeth to visualize to Booker (as well as herself, as it takes a few moments for her to understand the extent of her powers when she 'finds' the key) what the multiverse is and how it works. The other pairs really do exist in their own respective realities, but they are not consciously present in the scene and instead only appear as representations of their world.

The most important clue in my opinion however, is the fact that during the ending when Booker is drowned, all but one instance of Elizabeth (all those non-omnipotent versions whose Booker did not succeed in getting her to this point) vanish. Since she is Booker's daughter in every universe, erasing his existence from the baptism onward would prevent her from ever being born and so all of her instantiations should have vanished (ignoring the time-loop paradox at this point). In the established timeline, Elizabeth is always born after the baptism event and so should be affected, but even if she had been born before the pre-Baptism Comstock-to-be Booker in the final scene cannot be one who had a daughter (indicated by his bleeding nose in the boat and increasingly confused memories as a result of being fused with another version of himself) or the drowning would have no effect. So in every possible interpretation, all versions of her should vanish. That this does not happen strongly suggests that Elizabeth has transcended the space-time continuum (likely shifted into probability space) which avoids any time-related paradoxes and complications with unforeseen consequences (e.g. Clock Roaches).

Thus, the ending scene is more of a symbolic act that represents all (baptism-rejecting and -accepting) instantiations of Booker to emphasize both their sacrifices, which is supported by the generally anti-objectivist narrative, leaning heavily towards a Zen-like approach to dealing with the struggle that is life. Though many Bookers effectively die when their universes are closed, the drowning mainly serves to illustrate that Booker has to kill his self to really become free of himself by relinquishing his will to live and embracing death, thereby detaching himself from the world and Elizabeth, which she has to accept by letting him go.

The post-credit scene then can be interpreted in two ways:

It is real and Booker is alive. This means that Elizabeth erased all universes in which he became Comstock (and possibly stripped herself of her powers, returning to her infant self to give Booker a chance of living with his daughter). The Comstock-universes cease to exist because she wills it, not as a result of drowning Booker, because that happens before the baptism and there is no guarantee for any pre-baptism Booker to be one who would accept baptism.

OR

The scene is not real and something like a distant afterthought or melancholy figment of Elizabeth's imagination. In this case she erased every single universe, including the prime one, in an effort to end the cycle and eradicate not only all violence, but also all possibility of Booker (or someone like him) ever becoming (someone like) Comstock and building 'a city'. As an ultimate sacrifice, she could even remove herself from existence, thus erasing the entire Bioshock history.

Either way, one chilling implication of the ending, no matter which interpretation you choose, is that even in the most favourable situation she is ultimately responsible for single-handedly wiping out trillions of lives. One might argue that their timelines are erased as well, but from a metaphysical standpoint nothing can ever really be undone. From their subjective points of view those people experienced being alive and that perception is terminated.

In most other cases I would reject such an answer as a cheap cop-out, but in the case of this game, which is entirely based on the concept of parallel realities and pays great attention to detail, I think this epic and tidy solution manages to nicely connect most debated plot points and even enriches the story's dramatic impact. Personally, I prefer it to turning the plot into a convoluted mess of paradoxes and inconsistencies.